From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 420A1C43465 for ; Fri, 18 Sep 2020 13:44:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C28A20878 for ; Fri, 18 Sep 2020 13:44:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726126AbgIRNoM (ORCPT ); Fri, 18 Sep 2020 09:44:12 -0400 Received: from verein.lst.de ([213.95.11.211]:32784 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbgIRNoM (ORCPT ); Fri, 18 Sep 2020 09:44:12 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 8EEFA68B05; Fri, 18 Sep 2020 15:44:06 +0200 (CEST) Date: Fri, 18 Sep 2020 15:44:06 +0200 From: Christoph Hellwig To: Al Viro Cc: Christoph Hellwig , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200918134406.GA17064@lst.de> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918134012.GY3421308@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote: > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > > - return pt_regs_trap_type(current_pt_regs()) == 0x110; > > + return pt_regs_trap_type(current_pt_regs()) == 0x110 || > > + (current->flags & PF_FORCE_COMPAT); > > Can't say I like that approach ;-/ Reasoning about the behaviour is much > harder when it's controlled like that - witness set_fs() shite... I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks? From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Date: Fri, 18 Sep 2020 13:44:06 +0000 Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-Id: <20200918134406.GA17064@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> In-Reply-To: <20200918134012.GY3421308@ZenIV.linux.org.uk> To: Al Viro Cc: Christoph Hellwig , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote: > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > > - return pt_regs_trap_type(current_pt_regs()) = 0x110; > > + return pt_regs_trap_type(current_pt_regs()) = 0x110 || > > + (current->flags & PF_FORCE_COMPAT); > > Can't say I like that approach ;-/ Reasoning about the behaviour is much > harder when it's controlled like that - witness set_fs() shite... I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE31AC43463 for ; Fri, 18 Sep 2020 13:50:45 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3C48E206D9 for ; Fri, 18 Sep 2020 13:50:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C48E206D9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BtFbN4RGzzDqf1 for ; Fri, 18 Sep 2020 23:50:40 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BtFS20XgnzDqgl for ; Fri, 18 Sep 2020 23:44:16 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id 8EEFA68B05; Fri, 18 Sep 2020 15:44:06 +0200 (CEST) Date: Fri, 18 Sep 2020 15:44:06 +0200 From: Christoph Hellwig To: Al Viro Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200918134406.GA17064@lst.de> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918134012.GY3421308@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-mips@vger.kernel.org, David Howells , linux-mm@kvack.org, keyrings@vger.kernel.org, sparclinux@vger.kernel.org, Christoph Hellwig , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, Arnd Bergmann , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote: > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > > - return pt_regs_trap_type(current_pt_regs()) == 0x110; > > + return pt_regs_trap_type(current_pt_regs()) == 0x110 || > > + (current->flags & PF_FORCE_COMPAT); > > Can't say I like that approach ;-/ Reasoning about the behaviour is much > harder when it's controlled like that - witness set_fs() shite... I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96396C43464 for ; Fri, 18 Sep 2020 13:45:31 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2FE9E20684 for ; Fri, 18 Sep 2020 13:45:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="PVllGoff" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2FE9E20684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Co6TjfvSupYFvJepx+vnFGRQOynpz9tdT2WW67Jp72s=; b=PVllGoffmJkFsMScvq6FyNJO3 j4VVKYYDlLHZjEwGEO9R0AHQVv663F6djc+Uarvp/shNZNQvPmhRDa1XOakLpb07L2WLluAl0IDhS Uj3RhCuIzz2pGVQ2uRiL+hiz6JYeGeYAACQnkVWQXwB5PpW180+IDQSmHxd/ubmfi/LLKIQaHsnEk slIBbwJeJ9ljx6bVUCv8H3df1R9E0aKqEtUJz33dYziUWPkFeZPkZjnXRyb0XNdkyUfQgvgGi5xzV BVP3r6nhIEapQVUCJJQhs10EOykX0dinhe2XppA0tQU+HlJbBQTy/wZXLSOjOeAMiF3J7ZsdSTW12 T91xlxGIw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJGgR-0006Cs-7l; Fri, 18 Sep 2020 13:44:15 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kJGgO-0006Am-7x for linux-arm-kernel@lists.infradead.org; Fri, 18 Sep 2020 13:44:13 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 8EEFA68B05; Fri, 18 Sep 2020 15:44:06 +0200 (CEST) Date: Fri, 18 Sep 2020 15:44:06 +0200 From: Christoph Hellwig To: Al Viro Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag Message-ID: <20200918134406.GA17064@lst.de> References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200918134012.GY3421308@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200918_094412_404891_2C6469A9 X-CRM114-Status: GOOD ( 12.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aio@kvack.org, linux-mips@vger.kernel.org, David Howells , linux-mm@kvack.org, keyrings@vger.kernel.org, sparclinux@vger.kernel.org, Christoph Hellwig , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, Arnd Bergmann , linux-block@vger.kernel.org, io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 18, 2020 at 02:40:12PM +0100, Al Viro wrote: > > /* Vector 0x110 is LINUX_32BIT_SYSCALL_TRAP */ > > - return pt_regs_trap_type(current_pt_regs()) == 0x110; > > + return pt_regs_trap_type(current_pt_regs()) == 0x110 || > > + (current->flags & PF_FORCE_COMPAT); > > Can't say I like that approach ;-/ Reasoning about the behaviour is much > harder when it's controlled like that - witness set_fs() shite... I don't particularly like it either. But do you have a better idea how to deal with io_uring vs compat tasks? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel